Liquid fertilizing compositions

ABSTRACT

Liquid fertilizer compositions and methods of making liquid fertilizer compositions are set forth herein. In one embodiment, a liquid fertilizing composition includes an aqueous ammonium chloride solution having a pH between 6.5 and 8.5, a dispersant selected from anionic polyacrylamides, and a corrosion inhibitor. In another embodiment, a liquid fertilizing composition includes an aqueous solution having a pH between 6.5 and 8.5. The solution includes at least 16.5 percent by weight of ammonium chloride and between 0.5 and 1.0 percent by weight of dispersant. In yet another embodiment, a liquid fertilizing composition has a pH between 7.5 and 8.5. The composition consists essentially of at least 16.5 percent by weight ammonium chloride, between 0.5 and 1.0 percent by weight dispersant, an effective amount of corrosion inhibitor, and water.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 12/060,644, filed Apr. 1, 2008, now U.S. Pat. No. 7,674,312 which claims the benefit of priority to Provisional Patent Application Ser. No. 60/971,635, filed Sep. 12, 2007; the disclosure of priority to each of these filings is accordingly claimed, and the contents of each of these filings are incorporated herein by reference.

BACKGROUND

Fertilizers are often provided to plants to promote healthy growth. Liquid fertilizer compositions and methods of making liquid fertilizer compositions are set forth herein.

SUMMARY

In one embodiment, a liquid fertilizing composition includes an aqueous ammonium chloride solution having a pH between 6.5 and 8.5, a dispersant selected from anionic polyacrylamides, and a corrosion inhibitor.

In another embodiment, a liquid fertilizing composition includes an aqueous ammonium chloride solution having a pH between 7.5 and 8.5 and a dispersant selected from anionic polyacrylamides. The dispersant is present between 0.5 and 1.0 percent by weight.

In yet another embodiment, a liquid fertilizing composition includes an aqueous solution having a pH between 6.5 and 8.5. The solution includes at least 16.5 percent by weight ammonium chloride and between 0.5 and 1.0 percent by weight of dispersant.

In still another embodiment, a liquid fertilizing composition has a pH between 7.5 and 8.5. The composition consists essentially of at least 16.5 percent by weight ammonium chloride, between 0.5 and 1.0 percent by weight dispersant, an effective amount of corrosion inhibitor, and water.

In still yet another embodiment, a method of reducing a salt-out temperature and corrosivity of a liquid fertilizer having an initial pH less than 7.5, at least 16.5 percent by weight ammonium chloride, and between 0.5 and 1.0 percent by weight of a dispersant selected from anionic polyacrylamides is disclosed. The method includes the steps of raising the initial pH of the liquid fertilizer to a final pH between 7.5 and 8.5 and adding a corrosion inhibitor to the liquid fertilizer.

DETAILED DESCRIPTION

The application of compositions containing chloride (Cl⁻) ions is known to benefit crops in a variety of ways. Among other things, the uptake of chloride ions by crops has been shown to increase crop yield, reduce susceptibility to disease, reduce disease damage, accelerate plant development, improve kernel weight, and reduce late-season lodging. Sources of chloride ion commonly used as fertilizers include potassium chloride, magnesium chloride, and calcium chloride, though each of these sources has disadvantages.

In searching for an alternative to these sources, aqueous ammonium chloride solutions having between 16.5 and 30 percent by weight of ammonium chloride, and preferably 24 to 25 percent by weight of ammonium chloride, have been tested as fertilizers. These ammonium chloride solutions experienced substantial problems with salting-out. “Salting-out” is used herein to indicate the formation of precipitate. However, after extensive testing, it was discovered that combining one or more dispersants selected from anionic polyacrylamides, having the general formula:

with the aqueous ammonium chloride solution reduced or eliminated salting-out. A product having CAS number 25987-30-8 and marketed as Cyanamer® P-70 by CYTEC Industries Inc. of West Paterson, N.J. is one such dispersant. This product is referred to herein as CAS 25987-30-8, and it should be understood that the chemical composition, and not the manufacturer or marketer, is of interest.

Other suitable anionic polyacrylamides include, for example: Cyanamer® P-94 by CYTEC Industries Inc. of West Paterson, N.J.; APS 600 Series and APS 700 Series marketed by Applied Polymer Systems of Woodstock, Ga.; Soilfix IR, Percol 710, Percol 790, DP10-0434, and Soilfix LDP marketed by Ciba Specialty Chemicals, Inc. of Suffolk, Va.; Sioloc-PAM marketed by Hercules Environmental, Inc. of Doraville, Ga.; HydroPAM marketed by Stockhausen, Inc. of Greensboro, N.C.; CFM 2000 PAM; Bluwat Anionic Polyacrylamide marketed by Yixing Bluwat Chemicals Co., Ltd. of China; and CAS 25085-02-3; as well as derivatives and combinations thereof.

Table 1 shows the temperature at which the ammonium chloride solution combined with various amounts of CAS 25987-30-8 salted-out. In Table 1, solid conditions are marked as such, and “X” represents any presence of precipitate in which the entire composition was not completely solid. The compositions in Table 1 included 24 to 25 percent by weight ammonium chloride, the indicated amount of CAS 25987-30-8, and water; the pH of the compositions in Table 1 was 6.0.

TABLE 1 weight % CAS 25987-30-8 40° F. 36° F. 32° F. 30° F. 20° F. 15° F. 10° F. 0.75 X X X X 0.50 X X X X X X 0.375 X X X X solid solid 0.19 X X X X solid solid solid 0 X X X solid solid solid solid

As shown in Table 1, adding 0.75 percent by weight of CAS 25987-30-8 to the ammonium chloride solution allowed the product to be used at temperatures as low as 32 degrees Fahrenheit. Ammonium chloride with 0.75 percent by weight CAS 25987-30-8 has been used and sold by the present inventor with great success since 2004. Nevertheless, problems have arisen. Specifically, the product is corrosive and can destroy storage tanks.

To reduce the corrosivity of the composition, many corrosion inhibitors were tested, resulting in varying, but generally unsuitable, degrees of success. It was then determined that raising the pH of the ammonium chloride solution would alone reduce its corrosivity, and that adding a corrosion inhibitor in addition to raising the pH could also be beneficial. More particularly, raising the pH from approximately 6.0 to between 6.5 and 8.5, and preferably between 7.5 and 8.5, resulted in reduced corrosivity. Adding less than 0.1 percent by weight, and preferably approximately 0.05 percent by weight, of a corrosion inhibitor, such as NITROSolve™ 220, marketed by NALCO Company of Naperville, Ill., worked well in conjunction with raising the pH, as discussed above. NITROSolve™ 220 contains glycerol and a proprietary organic sulfonate. Effective amounts of other corrosion inhibitors (i.e., sufficient amounts to inhibit corrosion without significantly altering the fertilizing properties of the composition) may also be acceptable in conjunction with raising the pH as discussed above. Such corrosion inhibitors include, but are not limited to: products known as NITROSolve™ 330 and Protexo, both marketed by NALCO Company of Naperville, Ill.; P-35 by CYTEC Industries Inc. of West Paterson, N.J.; urea (46-0-0); corn steep liquor; as well as derivatives and combinations thereof.

Adding ammonia to the ammonium chloride solution is an effective way to raise the pH, although other methods would also be appropriate, including adding aqua ammonia and/or sodium hydroxide, for example. Adding ammonia may also increase the nitrogen (i.e., ammonia nitrogen) level of the fertilizer, from, for example, 5.5 percent to 6 percent. Even without adding ammonia to increase the pH, the ammonium chloride may provide a level of ammonia nitrogen, such as, for example, 5.5 percent by weight. Increased nitrogen levels have been shown to benefit crops.

Ammonium chloride may be obtained from waste sources, such as from spent batteries, or from the electronics industry where it is used to clean soldering irons, for example. Ammonium chloride obtained from waste sources will vary in pH depending upon the source, and will most likely contain impurities. Low levels of impurities may be insignificant to the present aqueous fertilizer compositions so long as the impurities are not present in a concentration that is unsafe for use in fertilizer. Alternatively, ammonium chloride with a standardized purity rating may be obtained directly from a chemical supplier.

The aqueous ammonium chloride fertilizer with increased pH and, optionally, one or more corrosion inhibitors is much less corrosive than an aqueous ammonium chloride fertilizer having a pH at or below 6. The composition having increased pH may thus allow the fertilizer to be safely stored in steel tanks and increase the useful life of applicators (i.e., sprayers).

Raising the pH of the ammonium chloride solution also has an unexpected synergic effect on the fertilizer's salt-out properties. Table 2 shows the temperature at which the ammonium chloride solution combined with various amounts of CAS 25987-30-8 salted-out when the pH of the ammonium chloride solution was raised from approximately 6.0 (Table 1) to approximately 7.8. In Table 2, solid conditions are marked as such, and “X” represents any presence of precipitate in which the entire composition is not completely solid. The compositions in Table 2 included 24 to 25 percent by weight ammonium chloride, the indicated amount of CAS 25987-30-8, and water; the pH of the compositions in Table 2 was 7.8. A corrosion inhibitor was not present in the compositions of Table 1 or the compositions of Table 2.

TABLE 2 weight % CAS 25987-30-8 40° F. 36° F. 32° F. 30° F. 20° F. 15° F. 10° F. 0.75 X 0.50 X X X 0.375 X X X 0.19 X X X solid 0 X X X X solid solid

As shown in Table 2, adding 0.75 percent by weight of CAS 25987-30-8 to an ammonium chloride solution with a pH of approximately 7.8 unexpectedly allowed the product to be used at temperatures above about 10 degrees Fahrenheit.

Because of the substantially lowered salt-out temperature, the aqueous ammonium chloride fertilizer can be applied from the fall through the early spring, which are times when the aqueous ammonium chloride fertilizer with a pH of approximately 6.0 could not have been effectively applied. Applying the fertilizer in the fall through early spring may increase yield between 7 and 12 bushels per acre; at today's market price, that could mean a revenue increase of $35 to $60 per acre. Similarly, the surprisingly low salt-out temperature may allow the aqueous ammonium chloride fertilizer to be applied in areas of colder climate with beneficial results.

Those skilled in the art appreciate that variations from the specified embodiments disclosed above are contemplated herein and that the described test results are not limiting. The description should not be restricted to the above embodiments or test results, but should be measured by the following claims. 

1. A liquid fertilizing composition, comprising: an aqueous ammonium chloride solution having a pH between 6.8 and about 8.5; an anionic polyacrylamide; and a corrosion inhibitor.
 2. The composition of claim 1, wherein the anionic polyacrylamide is selected from the group consisting of CAS 25987-30-8 and CAS 25085402-3.
 3. The composition of claim 1, wherein the anionic polyacrylamide is CAS 25987-30-8.
 4. The composition of claim 3, wherein the anionic polyacrylamide has a concentration between 0.5 and 1.0 percent by weight of the composition.
 5. The composition of claim 1, wherein at least one constituent of the corrosion inhibitor is selected from the group consisting of: (a) urea; (b) corn steep liquor; (c) glycerol; and (d) organic sulfonate.
 6. A liquid fertilizing composition, comprising: an aqueous ammonium chloride solution having a pH between 6.8 and 8.5; and an anionic polyacrylamide; wherein the anionic polyacrylamide is present between 0.5 and 1.0 percent by weight.
 7. The composition of claim 6, further comprising an effective amount of a corrosion inhibitor.
 8. The composition of claim 7, wherein: the anionic polyacrylamide includes at least one member selected from the group consisting of CAS 25987-30-8 and CAS 25085-02-3; the corrosion inhibitor is present between 0 and 0.1 percent by weight; and the corrosion inhibitor includes at least one member selected from the group consisting of: (a) urea; (b) corn steep liquor; (c) glycerol; and (d) organic sulfonate.
 9. A liquid fertilizing composition, comprising an aqueous solution of: at least 16.5% by weight ammonium chloride; and 0.5-1.0% by weight dispersant; wherein the aqueous solution has a pH of at least 6.8 and less than about 8.5.
 10. The composition of claim 9, wherein the dispersant includes an anionic polyacrylamide.
 11. The composition of claim 9, wherein the dispersant includes CAS 25085-02-3.
 12. The composition of claim 9, wherein the dispersant includes CAS 25987-30-8.
 13. The composition of claim 9, wherein the solution is aqueous at temperatures higher than ten degrees Fahrenheit.
 14. The composition of claim 9, wherein the ammonium chloride is obtained from a waste source and the solution includes impurities.
 15. The composition of claim 9, further comprising a corrosion inhibitor.
 16. The composition of claim 15, wherein: the corrosion inhibitor is present between 0 and 0.1 percent by weight; and at least one constituent of the corrosion inhibitor is selected from the group consisting of: (a) urea; (b) corn steep liquor; and (c) glycerol and organic sulfonate.
 17. A liquid fertilizing composition, consisting essentially of: Constituent Weight % ammonium chloride at least 16.5 Dispersant 0.5-1.0 corrosion inhibitor effective amount water Balance

and wherein the composition has a pH of at least 6.8 and less than about 8.5.
 18. The composition of claim 17, wherein the dispersant comprises a polyacrylamide.
 19. The composition of claim 17, wherein the dispersant has a CAS number of 25987-30-8.
 20. A method of reducing a salt-out temperature and corrosivity of a liquid fertilizer having an initial pH less than about 6.7, at least 16.5 percent by weight ammonium chloride, and between 0.5 and 1.0 percent by weight of at least one anionic polyacrylamide; the method comprising: raising the initial pH of the liquid fertilizer to a final pH between 6.8 and about 8.5; and adding a corrosion inhibitor to the liquid fertilizer.
 21. The method of claim 20, wherein: the corrosion inhibitor is present in a concentration between 0 and 0.1 percent by weight; and at least one constituent of the corrosion inhibitor is selected from the group consisting of: (a) urea; (b) corn steep liquor; (c) glycerol; and (d) organic sulfonate.
 22. A liquid fertilizing composition, comprising: an aqueous ammonium chloride solution having a pH between 6.8 and 8.5; a product having CAS number 25987-30-8; and a corrosion inhibitor. 